Combination SIS and vacuum bandage and method

ABSTRACT

A wound care bandage for treating a wound is provided. The bandage includes an SIS layer to be placed on the wound surface and a cover to placed over the wound. The bandage further includes a structure to provide a vacuum space. A method for promoting wound healing is further provided. The method includes applying the above-mentioned wound care bandage to the wound and creating a vacuum in the vacuum space to draw blood controllably from the wound into the SIS layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.09/855,287, filed May 15, 2001 now abandoned, which claims the benefitof U.S. Provisional Application Ser. No. 60/206,226, filed May 22, 2000,both of which are hereby expressly incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to wound care and more particularly to theprovision of an SIS wound care cover used in combination with a vacuumbandage. The invention contemplates both apparatus and a method forusing the apparatus.

It is known to use small intestine submucosa (SIS) in wound caretreatment, particularly the application of layers of SIS directly uponan open wound that has been debrided and cleaned. SIS is described inthe following U.S. Pat. Nos. 5,855,619, 5,866,414, 5,753,267, 5,762,966,5,755,791, 4,902,508, 4,956,178, 5,275,826, 5,281,422, 4,352,463,5,372,821, 5,445,833, 5,516,533, 5,573,784, 5,645,860, 5,641,518,5,711,969, and 5,695,998. These patents are hereby incorporated hereinby reference for purposes of disclosing the nature of SIS.

SIS has been described as a natural acellular biomaterial used torepair, support, and stabilize a wide variety of anatomical defects andtraumatic injuries. See, for example, Cook® Online New Release providedby Cook Biotech at “www.cookgroup.com”. The SIS material is a tissueengineered collagen matrix derived from porcine small intestinalsubmucosa that models the qualities of its host when implanted in humansoft tissues. Further, it is taught that the SIS material provides anatural scaffold-like matrix with a three-dimensional structure andbiochemical composition that attracts host cells and supports tissueremodeling. Surgisis™ Soft Tissue Repair Biomaterial and Oasis™ WoundDressing Biomaterial are available for remodeling partial thickness skininjuries (Cook Biotech, Bloomington, Ind.). The Oasis™ Wound Dressing isprovided in single thickness, fenestrated sheets. It will be appreciatedthat SIS is readily available for use as a wound dressing.

While small intestine submucosa is available, other sources of submucosaare known to be effective for tissue remodeling. These sources include,but are not limited to, stomach, bladder, alimentary, respiratory, orgenital submucosa. See, e.g., U.S. Pat. Nos. 6,171,344, 6,099,567, and5,554,389, hereby incorporated by reference. Further, it is known thatthese various submucosa materials may be derived from non-porcinesources, including bovine and ovine sources. Additionally, othercollagen matrices are known, for example lamina propria and stratumcompactum.

It is also known to use a vacuum treatment bandage for acceleratingwound healing. A vacuum bandage is a bandage having a cover for sealingabout the outer perimeter of the wound and under which a vacuum isestablished to act on the wound surface. This vacuum applied to thewound surface accelerates healing of chronic wounds. Typically, suctiontubes are provided for drawing exudate away from the wound, and thesuction tubes may be used to create the vacuum under the cover. If thecover is a flexible cover, which is typically more comfortable for thepatient, a porous packing may be provided under the cover to provide thespace in which the vacuum is formed. Additionally, it is known a heaterwithin a wound treatment apparatus to promote healing. The followingU.S. Pat. Nos. establish the nature of vacuum and/or heat treatmentbandages and devices: U.S. Pat. Nos. 6,095,992, 6,080,189, 6,071,304,5,645,081, 5,636,643, 5,358,494, 5,298,015, 4,969,880, 4,655,754,4,569,674, 4,382,441, and 4,112,947. All of such references areincorporated herein by reference for purposes of disclosing the natureof such vacuum or heat treatment of wounds.

As shown, for example, in U.S. Pat. No. 5,645,081 (hereinafter the '081patent), a method of treating tissue damage is provided by applyingnegative pressure to a wound. The negative pressure is provided insufficient duration and magnitude to promote tissue migration in orderto facilitate the closure of the wound. FIG. 1 of the '081 patentdiscloses an open cell polyester foam section covering the wound, aflexible hollow tube inserted into the foam section at one end andattached to a vacuum pump at another end, an adhesive sheet overlyingthe foam section, and tubing to adhere to the skin surrounding the woundin order to form a seal that allows the creation of a vacuum when thesuction pump is operating. The '081 patent further teaches use ofnegative pressure between about 0.1 and 0.99 atmospheres, and that thepressure can be substantially continuous, wherein the pressure isrelieved only to change the dressing on the wound. Alternatively, the'081 patent teaches use of a cyclic application of pressure inalternating periods of application and non-application. In a preferredembodiment, pressure is applied in 5 minute periods of application andnon-application.

The following pending applications, assigned to the same assignee as thepresent application is licensed, are also specifically incorporatedherein by reference: U.S. patent application Ser. No. 09/369,113 filedAug. 5, 1999 and titled Wound Treatment Apparatus, now U.S. Pat. No.6,458,109, U.S. patent application Ser. No. 09/725,352 filed Nov. 29,2000 and titled Vacuum Therapy and Cleansing Dressing for Wounds, nowU.S. Pat. No. 6,685,681, and U.S. patent application Ser. No. 09/725,666filed Nov. 29, 2000 and titled Wound Treatment Apparatus, now U.S. Pat.No. 6,755,807.

Various of prior art references teach the value of the vacuum bandage orthe provision of vacuum to the surface of a chronic wound. SeveralRussian language articles exist that establish the efficacy of vacuumtherapy. Examples of such prior art articles, each of which discussesthe use of application of vacuum to a wound to promote healing, are asfollows: Vacuum therapy in the treatment of acute suppurative diseasesof soft tissues and suppurative wound, Davydov, et al. Vestn. Khir.,September 1988 (“the September 1988 article”); Pathenogenic mechanism ofthe effect of vacuum therapy on the course of the wound process,Davydov, et al. Khirurigiia, June 1990 (“the June 1990 article”); andVacuum therapy in the treatment of suppurative lactation mastitis,Davydov, et al., Vestn. Khir., November 1986 (“the November 1986article”).

The Russian articles distinguish wound drainage from use of vacuumtherapy for healing, and they report that vacuum therapy results infaster cleansing of the wound and more rapid detoxification than withthe traditional incision-drainage method. The November 1986 articledescribes the vacuum therapy protocol as 0.8-1.0 atmosphere for 20minutes at the time of surgery, and subsequent 1.5 to 3 hour treatmentsat a vacuum of 0.1 to 0.15 atmosphere, twice daily. These Russianarticles teach that use of negative pressure accelerates healing. TheRussian articles further teach using this vacuum method to decrease thenumber of microbes in the wound. The June 1990 article teaches thatvacuum therapy provides a significant antibacterial effect. The June1990 article describes the stepped up inflow of blood to the zone aroundthe wound, which leads to an increase in the number of leukocytesreaching the focus of inflamation. Moreover, the Russian articles teachimprovement of local blood circulation using vacuum therapy. TheSeptember 1988 article teaches improved inflow of blood into the woundzone, which intensifies the repair processes. The June 1990 articleteaches that vacuum therapy promotes mobilization of blood plasma,intertissue fluid, and lymph into the wound. The June 1990 articlereports that cellular and non-cellular elements of connective tissueappear twice as quickly in wounds treated with vacuum therapy.Subsequent articles and patents further develop the benefits obtainedwith vacuum therapy. The prior art, therefore, teaches the benefit andvalue of a vacuum bandage.

SUMMARY OF THE INVENTION

According to the present invention, a wound care bandage is providedthat combines the advantages of SIS and vacuum therapy to control andenhance the flow of fluid from the wound bed and into the SIS material.The present invention, therefore, is a method for controllably drawingfluid from the surrounding tissue and into an SIS layer placed on thewound, thereby enhancing the healing and restructuring properties of theSIS.

The present invention comprises structure to provide a space above theSIS and the wound bed, in which space a vacuum is developed to causeblood flow from the wound bed into the SIS. Furthermore, the methodcontemplates controlling the vacuum level and the application time ofthe vacuum to present optimum blood flow from the wound bed into theSIS.

In preferred embodiments, the wound care bandage includes an SIS layerto be placed in contact with the wound bed. As mentioned above, thewound care bandage further includes a structure placed over the SISlayer to provide a vacuum space between the SIS layer and a cover placedover the structure and SIS layer. The cover is coupled to the patient'sskin surrounding the wound to provide a sealed environment. A vacuumsource is coupled to the wound covering for communication with thevacuum space created by the structure. The vacuum source is used tocreate a vacuum within the sealed environment in order to draw bloodfrom the wound bed up through the SIS layer to promote the healingprocess. The vacuum suction is to be at a level sufficient to draw bloodto the SIS layer, for example, 125 mm Hg. It will be appreciated,however, that varying levels of vacuum suction and varying protocols forthe duration of application of vacuum are within the scope of thepresent invention.

In further embodiments, the space-providing structure is a porous orreticulated pad or other structure having air passageways extending fromthe SIS layer to the cover. In still further embodiments, thespace-providing structure may be a foam ring, or it may be the coveritself, provided that the cover is sufficiently rigid.

Thus, in one aspect of this invention a wound care bandage is providedcomprising a collagen matrix formed for placement on a wound, a coverconfigured for placement over the wound to provide a sealed environmentaround the wound and adapted for communication with a vacuum source, anda structure for placement between the collagen matrix and the cover andconfigured to provide a vacuum space. In preferred embodiments, thecollagen matrix is a layer of submucosa.

In another aspect of this invention a wound care bandage is providedcomprising an SIS layer adapted to be placed on a wound, and a coverconfigured to be placed over the wound and the SIS layer to provide avacuum space between the SIS layer and an inside surface of the cover,the space being connectable with a vacuum source.

Still another aspect of this invention includes a method for promotingwound healing comprising the steps of providing a wound care bandagehaving an SIS layer adapted to be placed on a wound, a cover to beplaced over the wound to provide a vacuum space above the wound, astructure to define the vacuum space between the SIS layer and thecover, and creating a vacuum within the vacuum space to controllablydraw blood from the wound into the SIS layer placed over the wound.

Yet another aspect of this invention is directed to a method forpromoting wound healing comprising the steps of applying an SIS layer toa wound surface, placing a support structure over the SIS layer, placinga cover over the wound, SIS layer and support structure to define avacuum space, connecting the cover to a vacuum source, and creating avacuum within the vacuum space.

An additional aspect of this invention is directed to a method forpromoting wound healing comprising the steps of applying a collagenmatrix to a wound surface, creating a vacuum space in communication withthe wound and the collagen matrix, and generating a vacuum within thevacuum space in a magnitude and duration sufficient to draw blood fromthe wound into the collagen matrix.

A final aspect of this invention is a kit for promoting wound healing,the kit comprising a submucosa layer for contacting the wound, a porouspad, and a cover for creating a seal around the wound and configured forcommunication with a vacuum source.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is a sectional view of a debrided wound and a wound care bandageshowing an SIS layer, a porous pad or filler, and a cover of the woundcare bandage, and further showing the cover of the wound care bandage incommunication with a tube adapted to lead to a vacuum source;

FIG. 2 is a plan view of the SIS layer shown in FIG. 1 showingfenestrations in the SIS layer;

FIG. 3 is a sectional view of another debrided wound and another woundcare bandage including an SIS layer, a walled structure to provide avacuum space, a covering, and a vacuum tube positioned to lie under thecover and in communication with the vacuum space at one end and a vacuumsource an another end;

FIG. 4 is a sectional view of another embodiment of the presentinvention showing another wound care bandage over a debrided wound andshowing the bandage including an SIS layer, a ring-shaped structuredefining a vacuum space in communication with the vacuum source, and acover positioned over the structure; and

FIG. 5 is a sectional view of another embodiment of the presentinvention showing the bandage including a semi-rigid walled structurefor defining a vacuum space in communication with the vacuum source.

DETAILED DESCRIPTION OF THE DRAWINGS

A wound care bandage 10 is provided, as shown in FIGS. 1-5, for use witha debrided wound 12. Referring to FIG. 1, bandage 10 includes a smallintestinal submucosa (SIS) layer 14 which lies adjacent to a woundsurface 16 of wound 12. Bandage 10 further includes a cover 18 forplacement over wound 12 and a structure 20, 120, 220, or 320 positionedbetween SIS layer 14 and cover 18 in order to create a vacuum space 22.Cover 18 is coupled to a portion of the patient's skin 24 surroundingwound 12 in order to enclose wound 12, SIS layer 14, and structure 20,120, 220, or 320 within a sealed environment. Bandage 10 furtherincludes a means for communicating vacuum space 22 with a vacuum source26. The wound care bandage 10, therefore, combines the healingproperties of the SIS layer 14 with the acceleration provided by thevacuum therapy.

SIS layer 14, which is applied directly to wound surface 16, may befenestrated (or perforated) to prevent fluid accumulation below the SISlayer 14. Such fenestrations 28 are shown, for example, in FIG. 2.Equipment is available for fenestrating skin grafts and it iscontemplated that such equipment could also be used to fenestrate SISlayer 14. These fenestrations 28, or perforations, in the SIS layer 14permit blood from the wound 12 to migrate upwardly into the SIS layer 14and deposit cells to start the tissue growth in the SIS framework of theSIS layer 14.

Further, SIS layer 14 may be formed to include one single sheet of SISor multiple sheets of SIS. For SIS layer 14 including multiple SISsheets, the sheets may be positioned in any number of orientationsrelative to each other. It is further within the scope of the disclosurefor SIS layer 14 to have any reasonable thickness for its use in bandage10. It is also known in the art that larger sheets of submucosa may beformed by fusing multiple strips of submucosa tissue. See U.S. Pat. No.5,711,969, already incorporated by reference. In a preferred embodiment,SIS layer 14 is sized to fit the wound and is flexible in order to allowthe SIS layer 14 to conform to any complex wound or wound surface.Additionally, it is known to treat wounds with SIS provided in fresh,frozen, or lyophilized forms. Lyophilized SIS may be used in the driedform, or it may be hydrated prior to use.

In some optional embodiments, a biological glue 30 is provided betweenthe debrided wound surface 16 and the SIS layer 14 in order to hold theSIS layer 14 in a stationary position against the wound surface 16, asshown, for example, in FIG. 1. One type of biological glue 30 used maybe a fibrin sealant, for example. It is within the scope of thisdisclosure, however, to include any type of biological glue sufficientfor holding the SIS layer 14 stationary relative to wound surface 16.

SIS is intended to identify porcine small intestine submucosa. Whilereference is made herein to SIS, it will be appreciated that smallintestine submucosa may be obtained from other animal sources, includingcattle, sheep, and other warm-blooded mammals. Further, other sources ofsubmucosa from various tissue are known to be effective for tissueremodeling as well. These sources include, but are not limited to,stomach, bladder, alimentary, respiratory, and genital submucosa. Suchsubmucosa-derived matrices comprise highly conserved collagens,glycoproteins, proteoglycans, and glycosaminoglycans. Additionally,other collagen matrices are known that can act as a biologicalscaffolds. Thus, it is understood that while the preferred embodimentuses SIS, other collagen matrices may be used within the scope of thisinvention.

The structure of bandage 10, is provided to form vacuum space 22 betweenSIS layer 14 and cover 18. A structure supports cover 18 while providingair passageways to the wound surface 16 and the SIS layer 14. As shownin FIG. 1, the structure is preferably a reticulated or porous filler orpad 20 having airflow passageways (not shown) extending throughout pad20. It is preferred that pad 20 be rather flexible to conform to anycomplex wound or wound surface and to be comfortable for the patient.Further, it is preferred that the thickness of the structure is selectedto provide proper vacuum access to all parts of the wound to be served.It is further preferred that a thickness, t, of the reticulated flexiblepad 20 be approximately one to two centimeters. The reticulated orporous pad 20 may be cut by the surgeon to be larger than the SIS layer14 and even larger than the wound 12.

Although porous pad 20 has been described above, it is within the scopeof this disclosure to include any such structure which functions tocreate a space between the SIS layer 14 and the cover 18 and permits airflow from the wound 12 to transmit negative pressure to the woundsurface 16. As shown in FIG. 3, the structure 120 may be gauze, or, asshown in FIG. 4, the structure may be a foam ring 220 or other such ringto position cover 18 in spaced-apart relation to SIS layer 14. Ring 220includes an aperture defined by an inner wall 221 of the ring 220. Thevacuum space 22 is thus defined by the SIS layer 14, the cover 18, andthe inner wall 221 of ring 220.

Further, as shown in FIG. 5, for example, the structure may be a rigiddome or a preferably semi-rigid dome 320 which supports the cover 18above the SIS layer 14. Semi-rigid dome 320 includes a lower member 322adapted to lie adjacent the patient's skin surrounding wound 12, anupper member 324 normally spaced-apart from SIS layer 14, and a middlemember 326 for supporting the upper member 324 in spaced-apartrelationship with the SIS layer 14. Semi-rigid dome 320 may be generallydome-shaped, for example, as well. Although such examples as porous pad20, foam ring 220, and semi-rigid dome 320 have been provided asexamples for the structure, it is within the scope of this disclosurefor bandage 10 to include any space providing structure above the SISlayer 14 and below the cover 18 for communication with a vacuum service26.

Cover 18 of the bandage 10 lies over the space-providing structure tofully enclose the structure, SIS layer 14, and wound 12. Cover 18 iscoupled to the patient's skin 24 which surrounds the wound 12. Forexample, cover 18 may be a thin transparent, non-porous adhesive sheetto adhere to the surface of the skin 24 about the wound 12 to provide avacuum enclosure. An adhesive 33 for coupling cover 18 to skin 24 isshown in FIGS. 1 and 3-5. A product such as Tegaderm™ (3 M Health CareLtd., (St. Paul, Minn.)) would be suitable for the cover, for example.It is within the scope of this disclosure, however, to include anysuitable non-porous impermeable or semi-permeable sheet. While aflexible or semi-rigid sheet is preferred for patient comfort, a rigidcover, such as a glass dome, is within the scope of this invention. Whena rigid cover is used, a separate space-providing structure is notneeded, as the rigid cover may be configured to provide the vacuumspace.

In order to encourage blood flow to the wound 12 and wound surface 16,vacuum space 22 of wound care bandage 10 is connected with vacuum source26. A vacuum tube 32 may be provided, for example, for fluidcommunication with vacuum space 22 and vacuum source 26. As shown inFIG. 1, vacuum tube 32 is coupled to cover 18 and in communication withvacuum space 22. A first end 40 of tube 32 includes a collar 34 coupledto an aperture of the cover 18. As shown diagrammatically, a second end42 of tube 32 is coupled to vacuum source 26.

In other embodiments, as shown in FIGS. 3-5, for example, tube 32 isplaced under cover 18 and into vacuum space 22. Cover 18 is sealedaround tube 32 in order create a sealed environment for the vacuum tofunction properly. The vacuum may be provided by a suction tube disposedin the space and configured to draw excess wound drainage away from thewound. Another type of fluid connection system between a wound dressingand a vacuum source is disclosed in U.S. Pat. No. 4,969,880,incorporated herein by reference. Furthermore, while first end 40 oftube 32 is shown in FIGS. 3 and 4 as being located in the structure 120or 220, it is understood that first end 32 may be placed directly on theSIS layer 14. Additionally, it is understood that tube 32 may be aJackson-Pratt type drain, with holes distributed along its lengthadjacent first end 32.

The vacuum may be provided in vacuum space 22 for controlled periods oftime. For example, initially, the vacuum may be applied for a sufficienttime to draw blood into the SIS layer 14, such as up to 125 mm Hg, forexample. It will be appreciated that this invention contemplatesdeveloping different protocols for amounts of vacuum and applicationtimes. It will also be appreciated that the vacuum may be provided by aperforated tube positioned and configured to carry away excess wounddrainage.

In treating wound 12, a caretaker first cleans and prepares the woundsurface 16. Once wound surface 16 is prepared, bandage 10 is to beapplied to the wound. SIS layer 14 is positioned over the wound 12 tocover the prepared wound surface 16. Structure 20, 120, 220, or 320 isplaced over the SIS layer 14 to define the vacuum space and cover 18 isplaced over the wound 12, SIS layer 14, and structure 20. Cover 18 isconnected to a vacuum source 26. Finally, suction is applied to thevacuum space 22 in sufficient magnitude and duration to draw blood fromthe wound into the SIS layer 14. Optionally, a biological glue 30 may beplaced on the wound surface 16 prior to application of the bandage 10.

Vacuum may be applied at any magnitude or duration to promote inflow ofblood from the wound into the layer of SIS. Preferably, vacuum may beapplied from 0.1 to 0.99 atmospheres, and more preferably 0.1 to 0.15atmospheres. In one embodiment, vacuum is applied essentiallycontinuously until healing takes place. In another embodiment, vacuum isused in periods of application and non-application, and the structureand cover may be removed during periods of non-application. Thesealternating periods may include one or two periods of application eachday for several days. In another embodiment, the negative pressure isapplied in 5 minute periods of application and non-application.

It is known that SIS can be integrated into the wound and restructuredto resemble the surrounding tissue. Thus, while the magnitude andduration of application of vacuum may vary, in a preferred embodimentthe SIS remains on the surface of the wound for the duration oftreatment. In optional embodiments, additional layers of SIS may beadded as the SIS is integrated into the wound. The additional layers maybe smaller pieces to be placed on localized areas of integration, or,because the vacuum promotes blood flow into the SIS layer, may be fullsize pieces conforming to the size of the wound surface.

Thus, in one embodiment the present invention is a method for treatingwounds comprising the steps of preparing the wound surface, applying abandage to the wound, the bandage having an SIS layer secured over thewound and a cover above the wound and the SIS layer to define a vacuumspace between the SIS layer and the cover, and applying suction to thevacuum space to draw blood from the wound into the SIS layer.

Although this invention has been described in detail with reference tocertain embodiments, variations and modifications exist within the scopeand spirit of the invention as described and defined in the followingclaims.

The invention claimed is:
 1. A wound care system comprising a vacuumsource, and a wound care bandage for use with the vacuum source, thewound care bandage comprising: a collagen matrix which is configured tobe placed by a caretaker on a wound of a patient and to integrate intothe wound, a cover configured for placement over the wound to provide asealed environment around the wound, and a structure for placementbetween the collagen matrix and the cover and configured to provide avacuum space, the vacuum source being coupleable to the vacuum space andoperable to create a negative pressure in the vacuum space, thestructure being removable from the wound after integration of thecollagen matrix into the wound, wherein no sutures and no staples arepresent in the wound care bandage to hold either the structure or thecollagen matrix in place during communication of negative pressure tothe vacuum space by the vacuum source; wherein the structure comprises aring having an aperture defined by an inner wall of the ring and whereinthe vacuum space is defined by the collagen matrix, the cover, and theinner wall of the ring.
 2. A method for promoting wound healing, themethod comprising: applying a first collagen matrix to a wound surface,creating a vacuum space in communication with the wound and the firstcollagen matrix, including placing a structure adjacent the firstcollagen matrix, and generating a vacuum within the vacuum space in amagnitude and duration sufficient to draw blood from the wound into thefirst collagen matrix and to facilitate integration of the firstcollagen matrix into the wound surface with the structure beingremovable from the wound after integration of the first collagen matrixinto the wound, wherein no sutures and no staples are present in thewound care bandage to hold either the structure or the first collagenmatrix in place during communication of negative pressure to the vacuumspace by the vacuum source; wherein the structure comprises a ringhaving an aperture defined by an inner wall of the ring and wherein thevacuum space is defined by the first collagen matrix, the cover, and theinner wall of the ring.